Environmental medicine tool box for Pig Vets

John Carr

Murdoch University/Portec Australia

www.portec.com.au

Poor performance on pig farms is too often blamed only on pathogens. The farm staff and veterinary team spend too much time and emphasis on treating these “diseases” relying on identifying the bug and finding a suitable “medicine” to heal the pigs. However, in practice it is often better to promote health rather than treat disease. In production medicine, once an animal actually expresses clinical signs of disease, too much money has already been lost. In addition, the animal’s welfare and well-being has suffered – a major concern to the veterinarian.

This article discusses a systematic approach and details basic equipment to assist the veterinarian’s ability to assess a pig’s well-being and welfare and then change the pig’s environment where deficiencies are identified. The bigger challenge to today’s veterinarian is understanding animal husbandry sufficient depth to suggest meaningful changes.

When we start our clinical examination we quietly look over the “stable door” and observe.

The environment can be broken down into four major categories:

Water; Food; Floor and Air

The basic pig pen’s environmental components	A simple tool kit used in environmental medicine

Approach to environmental medicine

The first approach is to ask the pig whether it is comfortable and is displaying behaviour within normal parameters.

Possible abnormal pig behaviour can be considered in two broad patterns:

Acute

Before the clinician enters a building, the pigs should be examined in an undisturbed natural state to determine their acute welfare situation. Using the four categories, it is possible to note various normal and abnormal behaviours, which then can be examined in more detail.

Inadequate water space with aggressive actions between pigs – arrowed.	Inadequate feed space – every feeder is working and there are signs of aggression – pig arrowed.
Inadequate sleeping accommodation, some pigs have to sleep in the defecation area	Inadequate air quality. The pigs’ lying patterns indicate they are cold; note the piglets do not place their stomach onto the cold floor

Chronic

The pig’s defecation pattern indicates the area where the pig will not select to sleep. It is vital to examine the defecation pattern.

The two pens shown below are on the same farm. Why would some pigs defecate over the slatted area and sleep on the appropriate solid area whereas another group defecate over the solid area and thus sleep over the inappropriate slated area?

Appropriate The pigs are lying on the solid portion of the floor and defecating over the slats	Inappropriate Pigs defecating on the solid area and sleeping on the slatted area.

The pigs throughout the farm failed to sleep in the human designated solid sleeping area. Examination of the air flow within the building revealed the cause:

Cross-section of the building and air flow patterns:

The building was designed with a central slurry system. The pen is slatted above the slurry system with solid flooring area in the rest of the pen. The pigs are supposed to sleep on the solid portion and defecate over the slatted area. To encourage the pigs to defecate over the slatted area the drinkers are placed in this area.

Unfortunately, the ventilation system utilized a cross-flow automatic curtain sided system which has a low air speed. When the air flow was examined, the cold entry air entered the building and fell into the building into the passageway and solid floor area. The air then moved into the centre of the house at a speed greater than 0.2m/s – a draught. This encouraged the sleeping pigs to move away from the solid area to the more comfortable slatted area, despite the drinker wetting and cooling the slatted area. The pigs then choose to defecate in the cool solid area. This in turn caused the solid area to become wet and smelt of faeces. This encouraged more defecation. The fact the air at entry was not attached to the ceiling, potentiated the problem.

The building, while good for the farm accountant (a single slurry system is cheaper than two channels), totally ignored the natural requirements of the pig. The solutions would be:

• Abandon the low air speed system for a sealed fan ventilated building
• Enlarge the slurry system and provide a totally slatted (or solid area in the centre) building
• Stop using the building for pigs

Water

Tools required to examine the water supply

Collapsible 250 ml water cups
Measuring cup	Stopwatch	Small tape measure
Wrench	Multipurpose tool	Total dissolved solids meter

Systematic approach:

Observe the pigs using the drinkers

Observe the type of drinkers

Observe the position of the drinkers in the pen and their locality in relation to the feeders

Note the distance between the drinkers

Count the number of drinkers in the pen and number(s) available per pig

Note any drinkers which are dirty – this probably indicates that the drinker is not working

Measure the flow rate of water. In troughs note the depth of the water. In the farrowing area check every drinker

Note any environmental impact – frozen or hot water supplies

Measure the height and angle to the drinker

Note any drinker which is leaking

Determine the water quality – taste; salt concentration; faecal contamination and/or temperature for example

Where failures are determined, remove the drinker and examine in detail

Simple examples where there were problems with the water supply:

The farm problem accompanying the picture is highlighted in blue

The drinkers are too far from the feeders and the floor management results in variable height The farm suffered from a variety of vice issues and poor growth	A dirty drinker (arrow) should always raise alarm and needs to be urgently checked in detail. The reduction in water availability resulted in variable growth, increased aggression over the drinkers which became more acute as the pigs got bigger
There is no water flowing from the drinker – in any circumstance a severe welfare problem. Unfortunately both drinkers in the pen failed resulting in death from “salt” poisoning	Environmental conditions can impact the water supply The pigs in the hospital pen failed to recover before this freezing issue was realized – this is a serious welfare failing	Drinkers height must be corrected for the pigs The lack of water accounted for greasy pig disease on this farm
The drinker is twisted making water difficult to access and they are leaking The farm produced excess slurry and demonstrated variable growth rates and pneumonia	The quality of water should be acceptable for man to drink. If you are unwilling to drink the water, why should pigs? The palatability of the water restricted lactating sow feed intake.	Drinkers which are inadequate should be immediately fixed The damaged drinker was not used by pigs reducing their water availability

Feed

Tools required to examine the feeding system

	>3mm >2 mm >1mm <1mm
Tape measure to calculate feeder space	Feed sieve to measure particle size – Bygholm kit	Scale to measure weight of feed being feed

Systematic approach:

Examine the feed bin or feed storage area

Observe the pigs using the feeders

Observe the type of feeders

Observe the position of the feeders in the pen and their locality in relation to the drinkers and defecation area

Calculate the feeding space and the space available per pig

Note any feeder where feed is unavailable or is overflowing

Note any feed bin, pipeline or feeder which is leaking feed, particularly through the slats

Are the rough/sharp edges to the feeder which may cause injury to the pigs?

Determine the feed quality – particle size and palatability. Taste the feed. There should be no pig feed that should be harmful to man

Estimate age of any fly population in soiled feed to provide time basis for stockmanship observance

Note any feeder which is vulnerable to vermin attack

Examine if the correct feed weight/volume is being used

Simple examples where there were problems with the feeding supply

The farm problem accompanying the picture is highlighted in blue

Feed bins where the filling point was left open, exposing many tonnes of feed to the rain Over 30 tonnes of feed had to be disposed of after going mouldy	Feeders which are too close together. Restricted feed access and growth in the pigs over 30 kg resulting in a misdiagnosis of PMWS	Feeder blocked Increase in gastric ulceration and a misdiagnosis of pneumonia occurred on this farm
Broken feed bins, pipes and feeders all contribute to wasted spilt feed The sow in the stall was losing weight before this error was noted	Rhyzopertha dominica and other vermin can result in considerable loss of feed These insects resulted in many bags of spoilt feed and reduced FRC	Sharp edges to corroded holes in a feeder – which may injure the pigs and is wasting feed The FCR on the farm was higher than expected and was not resolved until the feeders were fixed

Evaluation of stockmanship/feeder management using the fly (Musca domestica) in soiled feed

Eggs – less than 1 day	Maggots – 1 to 10 days
Pupae - 10 to 20 days	Hatched pupae – greater than 20 days

Estimation of fly lifecycle in days at 20°C

Floor

Tools required to examined the floor

The floor includes any surface where the pig has contact and the slurry system

Tape measures are essential to measure flooring conditions. The arrowed measure uses ultrasound	Calculator is useful to calculate stocking densities	An angle measure for loading area assessments – many countries have a legal 20° maximum slope

Systematic approach:

Calculate stocking rate (m²/pig)

Examine location, size and suitability of sleeping area

Examine pens for sharp and projecting edges, especially at bottom of doors and gates

Examine floor conditions for rough areas and holes. Pay particular attention to the floor under drinkers and feeders. Where different floor materials meet (e.g. metal and concrete) corrosion is common.

Check any bedding especially for mould

Check slat condition especially edges. Note solid and void widths.

Examine steps and gate separations

Examine building supports for damage by the pigs

Examine hygiene of pens, especially empty pens

Note the degree of unused floor space – such as passageways

Review the slurry system and hygiene cleaning programmes

On the outside of the building note condition of guttering and wall security

Simple examples where there were problems with the floor

The farm problem accompanying the picture is highlighted in blue

Overstocking in a serious health problem and a cause of serious welfare reduction The farm suffered from significant pneumonia and poor growth rates	Under-stocking can also be a problem resulting in cold pigs Placing the end pigs in a pen results in the cold pigs eating but not putting on weight stalling of their growth	Sharp projections may occur even in the pen, here the floor is falling apart (arrow) One of the pigs impaled itself on the damaged floor requiring stitching
Examine the pigs for signs of injury – scar from a wall projection (arrowed) This pig tore itself on a mis-positioned drinker.	Holes in the floor resulting in serious leg injuries A mating sow and boar both suffered injury when they slipped into this hole	Mould on bedding The farm had a significant abortion storm after this straw was used as bedding for pregnant sows
Roughened slats, especially in front on feeders or drinkers The farm reported numerous lame pigs and several pigs were euthanased as unfit for transport increasing post-weaning mortality	Steps can limit access to feeders by small pigs Small pigs were unable to reach the feeders and wasted significantly, resulting in a misdiagnosis of PMWS	Gating incorrectly hung can result in pigs getting caught between the bars Pigs caught by gates often die through strangulation. This pig was lucky
The building supports (especially when wooden) can be destroyed by pigs over time The building had to be abandoned as the pigs had weakened the roof supports	Poor cleaning between batches. This was part of an eradication programme and the farmer believed the farm was clean. Even this degree of feaces can spread dysentery (Brachyspira hyodysenteriae)	Poor layout design. In this particular case: note solid part of slat (arrow) within stall, sow’s faeces are more difficult to remove – more vulval discharges observed

Air

The air includes all aspects of ventilation and lighting regimes.

Tools required to examine the air

Ambient air temperature and humidity pen	Infrared thermometer	Pollutant analysis – gas concentration immediate and time based. NH3, H2S, CO2, CO
Light meter	Tachometer for fan speed	Tape measure for fan size
Smoke emitters come in a variety of sizes	Anemometers (and wind vanes) to measure air speed	Remote sensors to record changes over time

Systematic approach:

From the outside of the building: visually check air inlets and outlets for hygiene and maintenance. This might necessitate climbing into the attic space

Observe and account for the lying patterns of undisturbed sleeping pigs

From the inside of the building: visually check air inlets and outlets for hygiene and maintenance.

Check ambient air temperature and humidity at the: air inlet; pig height in the sleeping area and at the air outlet. This provides a minimum/ideal and maximum temperature range in the house

If floor heated areas are used, record the infra-red temperature emitted from the floor and variations in temperature over the surface

Examine any heat lamps. If gas heating is used note hygiene of heater and the colour of the flame

Examine the cooling system. Note if the water sprays into any feeder. Note distribution of water over evaporative cooling systems

Note any insulation failure issues

Note any signs of condensation

Note any pollution issues – gases, dust or endotoxin concentrations

Record the light intensity and patterns

Examine any automated ventilation systems for hygiene, maintenance and fan efficiency – sound, speed and size of fan

In pressurized rooms note pressure differences and changes in fan speed when door opened

Note any recording or alarm systems and check that they work within expected parameters

Note any open doors and holes in the walls

Review vermin control through the ventilation system

Expose and record air movement throughout the house by the use of smoke. Note the differences between hot and cold smoke when assessing air movement. It might be necessary to move outside the building to assess air movement between rooms and buildings

Record the air speed in the sleeping area and at air inlet

Note the time it takes the smoke to dissipate – room air exchange times

Examine any evidence of poor electrical maintenance

If necessary, set up time analysis of temperature and pollutant variations

Simple examples where there were problems with the air and ventilation systems

The farm problem accompanying the picture is highlighted in blue

Winter inlet (Soffit) blocked – the building is starved of air The pigs were suffering from a severe APP outbreak before this was resolved	The louver protecting the building is broken allowing draughts to enter the building The pigs post-weaning demonstrated significant diarrhoea problems	The heated floor is too cold in the farrowing house. The chilled piglets had E. coli scour before this was resolved. Heated floors pre-weaning should run at an infrared temperature of 36-42°C
Ventilation system impaired by other equipment (arrow) The performance of the pig’s were suboptimal before this was resolved	Cooling system clearly not working The finishing performance was poor until proper cooling was provided	Poor water distribution over an evaporation panel (dark/wet normal) Poor temperature control in the farrowing area with reduced feed intake in sows and poor weaning weights

Variation in inlet openings (arrow closed) The performance was variable over the house and between pens	Insulation area used for nesting As the farm aged, its performance deteriorated, in particular pneumonia increased	Poor lighting associated with electrical failure and fly dirt Gilt cycling was poor after arrival until a proper lighting regime implemented
High dust levels can damage pigs’ respiratory systems The post-weaning performance was poor and coughing very noticeable in these pigs	Alarms and sensors need to work also note side panels (A and B) are not working together An APP problem was diagnosed on the farm, but proper ventilation control resolved the issues	Holes in curtain result in draughts Poor room ventilation controls and variable growth throughout the house was noted
Smoke revealing high air speed The draught resulted in pigs having no sleeping area and increased vice and pneumonia	Ventilation between rooms and buildings need assessment This farm has no all-in/all-out as each room's ventilation was passed into the next room. Pneumonia was a serious problem.	Electrical failure can result in a farm fire The poor wiring resulted in a small electrical fire, but the ventilation failure resulted in the suffocation of 200 finishing pigs
External position of building Particularly with cross-flow ventilated barns it is necessary to consult a wind-rose to correctly orientate building	Obstructions to the whole farm ventilation The trees in the background restricted air movement to the farm and cause air vortexes which interfered with air flow	Obstruction to a buildings ventilation This building suffered from chronic pneumonia problems until the vegetation blocking the vents was removed

Most under-utilized tool set- YOU

The veterinarian

The veterinarian comes already equipped with a complex tool set allowing detailed examination of the pig’s environment through hearing, sight, smell, taste and touch. Combined with a trained analytical approach, and a knowledge base (PDA), the veterinarian is ideally situated to improve the welfare and well-being of pigs under his/her care.

Combination of problems

Environmental medicine should encompass the whole farm including the outside of the building and the general layout. Many times, farms have illustrated multiple problems at the same time.

For example, what problems can be seen in the photograph below?

Answers -at the end of the article

Examples of common disorders which have been resolved solely by manipulation of the environment

Water issues	Feed issues
Cystitis	Gastric ulceration
Pyelonephritis	Variable growth rates
Vaginitis/vulval discharges	Vices in general – tail biting
Greasy pig disease	Greasy pig disease
Vices – vulval biting	Colitis issues
Milking reduction	Milking problems – reduction
Facial necrosis	Facial necrosis
Non specific colitis	Post-weaning diarrhoea
Constipation	Mycotoxins – abortions/reproductive issues
Gastric ulcer	Regular and irregular returns
Enzootic pneumonia – tracheitis/bronchitis
Variable growth rates
“salt” poisoning
Atrophic rhinitis – bent snout
Floor issues	Air issues
Lameness general	Enzootic pneumonia – NH3 dust and endotoxin
Torn claws	Pneumonic conditions
Abrasions	Atrophic rhinitis – NH3 and dust
Septic arthritis	Sneezing and coughing – dust and endotoxin
Abscesses	Vices in general
Pleurisy	Scouring pre-weaning - draughts
Pulmonary abscessation	Scouring post-weaning - draughts
Pneumonia – overstocking	Sudden death – H2S pneumonia
Colitis – under-stocking/chilling	Greasy pig disease
Vices in general	Milking problems due to heat
Greasy pig disease	Reproductive disturbances – heat and cold
Reproductive issues/mating injuries	Poor cycling in gilts – light issues
Teat and udder damage	Meningitis – CO and other gases
Teat necrosis in piglets
Overlaid piglets
Splayleg in piglets

Summary

After 25 years of practising veterinary medicine the lesson I have learnt is that (excluding PMWS) almost all of the day to day conditions/disorders of the pig can be traced back to problems with stockmanship and man’s manipulation of the pig’s environment. Even in cases of PMWS a biosecurity breach lies at the bottom of the problem. There is no excuse for pre- or post-weaning diarrhoea, pneumonia or lameness issues on most farms. The majority of reproductive issues lie at the stockpersons feet to resolve. The veterinarian must recognise the impact of the environment in management of stress of pigs under their care and take positive holistic action to resolve the underlying issues, rather than just reaching for a convenient quick fix of medicine.

Combination of problems - answer

Problems:

• The air exhaust layout The air intake being above the air exhaust resulted in significant amount of recirculation of air within the facility. This increased respiratory pathogens and the amount of pneumonia accordingly. Post-weaning mortality was higher than expected.
• Position of feed bins The air exhaust – hot and damp, blew straight onto the feed bins. This resulted in condensation on the inside of the feed bin. The feed in the bin became mouldy. The mould reduced the concentration of Vitamin E and increased the amount of mycotoxins. Both of these factors reduced the immunity of the pigs; increasing the severity of clinical pneumonia. The condensation resulted in feed clumping and blocking of feed lines and feed bins. This resulted in feed outage problems, gastric ulceration and occasional sudden deaths associated with mulberry heart. Sub-clinically, there was decreased growth rates and food conversion efficiency reduction. The feed bins corroded quicker than expected, increasing costs.
• The position of the water lines The water line was not sufficiently insulated and in the winter the external temperature would drop to -25°C during the day! The water would freeze, resulting in inadequate water supplies: decreased feed intake, reduced growth rates and poor post-weaning performance.

All of this would have been missed if the veterinarian stayed inside the building

and only looked at the pig’s clinical signs